Xanthenium compounds and a process of preparing them



United States Patent XANTHENIUM COMPOUNDS AND A PROCESS OF PREPARING THEM Herbert Bestian and Gustav Schfifer, Frankfurt am Main Hochst, and Ferdinand Quint, Frankfurt am Main, Germany, assignors to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius und Bruning, Frankfurt am Main, Germany, a company of Germany N0 Drawing. Application December 23, 1952 Serial No. 327,668

Claims priority, application Germany December 31, 1951 7 Claims. (Cl. 260--315) The present invention relates to xanthenium compounds and a process of preparing xanthenium compounds.

U. S. applications Serial Nos. 234,665 and 270,102 for Triphenylmethane Dyestuifs,-filed June 30, 1951, in the name of Gustav .Schater, and February 5, 1952, in the names of Gustav Schafer and Ferdinand Quint, respectively, relate to a process of preparing dyestuffs of the triphenylmethane series, wherein resorcinol-sulfophthaleines are caused to react with primary or secondary amines after replacement of the hydroxyl groups, which are in para-positions with respect to the central carbon atom, by exchangeable atoms or atom groups. In this case, the benzene nucleus carrying the sulfonic acid group may contain substituents. The said specification, however, discloses .only symmetrical dyestuffs into which the same amino compound has been introduced twice.

Now we have found that asymmetrical Xanthenium compounds are obtained by causing 9-phenyl-Xanthhydrol-2-sulfonic acid compounds, which contain in 3.6- position replaceable atoms or atom groups and which may further contain substituents in the benzene nucleus carrying the sulfonic acid group, to react with primary or secondary aromatic amines at a low or moderate temperature and, if desired, sul-fonating the condensation products obtained.

In the above formulae X represents an atom or an atom group capable of being replaced, especially a halogen atom, R1 represents hydrogen or an aliphatic or cycloaliphatic radical, for instance methyl, ethyl, propyl, isopropyl, butyl or amyl, and R2 represents an aromatic radical. Furthermore, the benzene nucleus carrying the sulfo groups may contain substituents such as halogen atoms, hydroxyl groups, al-koxyl groups, carboxylic acid or sulfonic acid groups. The xanthenium compounds used as parent material and corresponding to Formula 1 above, can, for instance, be obtained by condensing benzene-2-sul-fonic acid-l-carboxylic acids with resorcinol in the presence of phosphorus oxyhalides or from resorcinol-sulfop'hthaleine by replacing the hydroxyl groups which are in para-positions with respect to the central carbon atom, by atoms or atom groups which are capable of being replaced. In this way, for instance, halogen atoms or alkoxy groups can be introduced.

In the preparation of symmetrical triphenyl-methane "ice dyestuffs according to the processes disclosed in the above mentioned applications wherein the reaction of phenylxanthhydrol-sulfonic acid compounds, containing in 3.6- position atoms or atom groups capable of being replaced, with amines is effected in the molecular proportion of 1:2, blue to red dyestufis are obtained which have a structure analogous to that of the violamines, i. e. the dyestufis obtained from dichloro-fluorane and amines. It is known that in the preparation of violamines both halogen atoms of dichlorofiuorane enter simultaneously into reaction. It is not possible in this series to isolate, in a satisfactory yield, asymmetrical reaction products from 1 mol of dichloro-fiuorane and 1 mol of amine. It is, therefore, very surprising that the replaceable atoms or atom groups in the p'henylxanthhydrol-sult'onic acid compounds can be reacted in stages with aromatic amines so that unilateral reaction products are obtained, the reaction having taken place in the molecular proportion 1:1. The unilateral reaction products can be isolated in a very good yield and in a very pure state. Low tem- .peratures, dilution of the reactants with solvents, and avoidance of a great excess of the base promote the .formation of unilateral condensation products and prevent the formation of the triphenylmethane dyestuffs described in the applications mentioned above. ;The unilateral reaction also takes place in the presence of a large excess of the "base if the temperature is kept at a value at which the bilateral reaction does not occur. Preferably, the reaction is carried out at temperatures below C.; the most favourable temperature depends upon the reactivity of the amine and the concentration of the reactants. Water and alcohol are particularly suitable solvents and diluents. By addition of acidbinding agents, the reactions can be facilitated and completed.

-In most cases, the final products separate in the form of well-developed colored crystals in an almost quantitative yield. They may serve as parent materials for dyestufis and can themselves be used as dyestuffs, either directly or after sulfonation.

The following examples serve to illustrate the invention, but they are not intended to limit it thereto, the parts being by weight unless otherwise stated, and the relationship of parts by weight to parts by volume being the same as that of the kilogram to the liter.

The present invention especially pertains to Xanthenium compounds of the following general formula:

wherein R1 stands for hydrogen or a lower alkyl radical, R means an aromatic radical and R3 stands for hydrogen, halogen, the methoxy group, the carboxylic acid or sulfonic acid group.

R1 may represent hydrogen or a lower alkyl radical such as methyl, ethyl, propyl, isopropyl, butyl or amyl. R2 may bean aromatic radical containing one or more aromatic nuclei which can be connected directly or by means of an intermediary atom or atom group. R2 may be an aromatic hydrocarbon radical or an aromatic radical substituted by one or more atoms or atom groups, such as halogen, hydroxyl, alkyL-aralkyl, cyclo-alkyl, alkoxy, aryloxy, nitro, substituted or unsubstituted amino- 3.6-dichloro-9-phenyl-xanthhydrol-2'-sulfonic 3 carboxylic acid, sulfonic acid, sulfonic acid amide, sultone-especially hydroxyethyl-sufonetrifluoromethyl groups or other groups. Of special value may be R2- radicals wherein the hydroxy group and the carboxylic acid group are present as substituents of adjacent carbon atoms. Furthermore, R2 may be an aromatic radical formed by condensation or substitution of an aromatic nucleus by a heterocyclic ring.

A great number of primary or secondary amino compounds containing the radicals R1 and R2 are named in the examples given hereinafter but the invention is not limited thereto.

Example 1 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfonic acid are stirred with 75 parts by volume of methanol for minutes at room temperature. 4.65 parts of aniline are rapidly introduced into the yellow magma obtained. Reaction sets in very quickly with a slight rise of temperature. The internal salt of acid dissolves and, after a short time, the reaction product of the formula indicated below precipitates in the form of small crystals having a bronze lustre. The whole is stirred for 1 hour at room temperature, the product is filtered off with suction and the crystal cake is washed with methanol and hot water. Yield: 9.17 parts of a brown-red glittering crystalline powder.

Example 2 then separated in the form of small iridescent crystals,

which are filtered off with suction and washed several times with alcohol. The filter cake is stirred with 200 parts by volume of hot water which had been made acid to Congo red paper by means of 1 part by volume of concentrated hydrochloric acid. The product is filtered oil with suction, washed with hot water and dried. Yield: 19.3 parts.

Example 3 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfonic acid are stirred with parts by volume of n-but-anol. Thereupon there is added a solution of 4.1 parts of para-nitroaniline in 40 parts by volume of'n-butanol, having a temperature of C. C. The reaction sets in while the mixture turns red, and the condensation product crystallises after a few seconds. The reaction mixture is slowly heated to C. C. After heating for /2 hour at 80 C.90 C., the product is filtered ofi with suction while still hot and washed several times with methanol. 10.2 parts of a brown, soft powder are obtained.

Example 4 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfonic acid are, at roomtemperature, stirred for 15 minutes with'20' parts by volume of ni. butanol. Thereupon a warm solution of 4.8 parts of 2-nitro-4-toluidine in 50 parts by volume of n-butanol is run in and the whole is heated slowly under reflux to gentle boiling. The condensation product soon separates in the form of red crystals. The mixture is kept boiling gently for 1 /2 hours; it is then allowed to cool to 50 C.60 C., filtered while still warm, and the product Washed several times with methanol until the methanol liquor running through is of a light color. Yield: 4.6 grams of a brick red powder.

Example 5 8.1 parts of the internal salt of 3.6-dichloro-9-phenyl- Xanthhydrol-2'-sulfonic acid are stirred for 15 minutes With 30 parts by volume of alcohol. Thereupon a solution of 7.74 parts of 1-amino-2-methoxybenzenes-S-sulfonic acid diethylamide in 50 parts by volume of alcohol having a temperature of 50 C.60 C. is run in. The reaction product separates immediately. The mixture is heated for an additional 2 hours at 50 C.60 C., filtered with suction while still warm and the product washed repeatedly with methanol. The new compound is obtained in the form of a bright brick red powder. Yield: 12.45 parts.

Example 6 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxamthhydrol-2-sulfonic acid are stirred for 15 minutes with 30 parts by volume of methanol until a homogeneous yellow paste has formed. The mixture is cooled to 5 C.l0 C. and a solution of 4.5 parts of para-aminoacetanilide in 60 parts by volume of methanol is run in. Reaction sets in immediately with a blue-violet coloration and the colored condensation product crystallises out. Stirring is continued for 1 hour, 1 part by volume of a solution of 20 parts of potassium acetate in parts by volume of methanol is added, the reaction product is filtered 011 with suction after 15 minutes and washed on the suction filter with methanol. The new compound is obtained'in a yield of 9.2 parts in the form of a dark brown powder which dissolves in hot glycol with a bluish red color.

Example 7 16.2 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfonic acid are stirred with 60 parts by volume of methanol to a yellow homogeneous paste. A solution of 16.8 parts of B-amino-N-ethylcarbazole in parts by volume of methanol is added while stirring vigorously. Reaction sets in instantaneously and the condensation product crystallises at once. Stirring is continued for 2 hours at room temperature, the product is filtered off with suction and washed with methanol. For further purification the filter cake is stirred at 80 C. with 250 parts by volume of very dilute hydrochloric acid, the prodnot is filtered off with suction while hot and washed repeatedly with hot water. Yield: 21.6 grams of a black powder.

Example 8 Example 9 40 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfoni-c acid and 69 parts of 3-amino-4- methoxyphenyl- 8-hydroxyethy1 sulfone are stirred with 600 parts by volume of alcohol and heated for 1 hour under refiuxto gentle boiling. During the operation the condensation product crystallises in the form of brick red crystals which are filtered oil with suction at'40 C.- 50 C. The filter cake is stirred for 15 minutes at 80 C. with 500 parts by volume of water, filtered again and washed With hot water. After drying there are obtained 46 parts of a claret powder.

Example 1 0 8.1 parts of the internal salt of 3.6 dichloro-9-phenylxanthhydrol-2'-sulfonic acid and 10 parts of 4-amino- 3.5-dimethylphenyl-p-hydroxyethyl sulfone in 25 parts by volume of glycol are heated for 4 hours at 100 C. The starting compounds dissolve. From the deep brown-red solution the condensation product separates towards the end of the heating in the form of yellow-red crystals. The mixture is allowed to cool to 50 C.=60 C., 100 parts by volume of N-hydrochloric acid are added drop- Wise and a further 400 parts by volume of water are slowly run in. The product is filtered off with suction and washed repeatedly with water on the suction filter. Yield: 8.95 'parts' of a brown powder.

Example 11 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2-sulfonic acid and 7.65 parts of l-amino- 2-hydroxy-3-benzoic acid are stirred with 150 parts by volume of alcohol and heated for 2 hours under reflux to gentle boiling. The condensation product separates already after a short heating. The product is filtered with suction at 40 C.-50 C. and the filter cake is stirred for 15 minutes at 80 C. with 200 parts by volume of water, which has been acidified with 5 parts by volume of concentrated hydrochloric acid. The product is filtered ofif again, washed with hot water and dried. Yield: 10.1 parts of a brick red powder which dissolves readily in dilute alkalies imparting a red color to the solution.

In the same way 1-amino-3-hydroxy-4-benzoic acid, l-amin'o-4-hydroxy-5-benzoic acid, l-arnino-3-methyl-4- hydroxybenzene-5-carboxylic acid, l-am-ino-2-methyl-4- hydro'xybenzene-5-carboxylic acid and l-ainino-2-hydroxy- 5-methylbenzene-3-carboxylic acid can be reacted with the internal salt of 3.6-dichloro-9-phenyl-xanthhydrol-2- sulfonic acid.

Example 12 16.2 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2-sulfonic acid are introduced into a solution of 15 parts of 1-amin0-2.6-dimethylbenzene in 30 parts by volume of methanol. The solution soon turns deep red while the added compound dissolves. In order to complete the reaction the solution is heated for 30 minutes to 60 C.-70 C. The very dark syrupy solution that has formed is added slowly, while stirring, to 200 parts by volume of hydrochloric acid of 2.1 percent strength. The condensation product precipitates in an amorphous state. In order to convert it into a well defined crystalline product it is heated for /2 hour at 70 C.- 80 C. It is filtered with suction while hot and washed repeatedly with hot water. Yield: 18.9 parts of a brick red powder which dissolves easily in methanol or alcohol with a yellow-red color.

The reaction of the internal salt of 3.6-dichloro-9- phenyl xanthhydrol-2'-sulfonic acid with 1-amino-2.4.6 trirnethylbenzene (mesidine) is carried out in the same manner. The condensation product is obtained in an almost theoretical yield as a bright brick red, voluminous crystalline powder.

Example 13 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfonic acid are introduced into a solution of parts of l-methylamino-Z.5 dimethylbenzene in 20 parts by volume of methanol. The whole is heated under reflux for /2 hour to gentle boiling. The mixture is worked up by means of dilute hydrochloric acid, with subsequent heating, as described in Example 12. 8.5 parts of a brick red voluminous powder are obtained.

Instead of 1-methylamino-2.S-dimethylbenzene, the same quantity of 1-methylamino-Z-methylbenzene may be used. 9.2 parts of the corresponding condensation product are obtained as a brown-red voluminous powder, which dissolves easily in methanol or alcohol with a yellow-red color.

Example 14 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol 2-sulfonic acid, 10 parts of 1-amino-2- methyl-6-chlorobenzene, and 20 parts by volume of methanol are heated for 2 hours under reflux to gentle boiling. The major part of the condensation product crystallis'e's already after 1 hour. The mixture is allowed to cool and 50 parts by volume of 2 N-hydrochloric acid are added dropwise. The condensation product crystallises almost completely. It is filtered off with suction and washed repeatedly with hot water. Yield: 9.7 parts of a brick red powder consisting of coarse crystals.

Example 15 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2-sulfonic acid, 9.6 parts of l-amino-Z-trifluoromethylbenzene and 50 parts by volume of alcohol are heated for 6 hours under reflux to gentle boiling. The former compound dissolves slowly while the solution assumes a red coloration. From the boiling solution the condensation product separates already after a short time in well formed rhombic crystals. The mixture is allowed to cool, is filtered with suction and the residue washed repeatedly on the suction filter with alcohol until the wash liquor has a weak yellow color. Yield: 9.2 parts of a bright yellow-red crystalline powder with a weak bronze lustre. 4

Example 16 507 'C., is filtered with suction and the residue washed,

repeatedly with methanol. Yield: 10.8 parts of a brownred voluminous powder.

Exam le 17 8.1 parts of the internal salt of 3.6-dichloro- 9-phenylv xan'thhydrol-2-sulfonic acid and 50 parts by volume of methanol are stirred for 30 minutes. To the yellow homogeneous paste there is added a hot solution of 9 parts of Lamina-3.2'-dimethyl-azobenzene in 50 parts by volume of methanol. The yellow-red color changes rapidly to dark red and after a short time the condensation product commences to crystallise. Stirring is continued for 3 hours and 2 parts by volume of a solution of 20 parts of potassium acetate in parts by volume of methanol are added. After 15 minutes the mixture is filtered with suction and the residue washed with methanol. For further purification the filter cake is stirred with 200 parts by volume of water at 80 C., filtered off with suction and dried. Yield: 12 parts of a brown-red powder.

Example 18 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2-sulfonic acid are quickly introduced into a warm solution of 9.5 parts of 1-(4'-aminophenyl)-3- methyl-'S-pyrazolone in parts by volume of methanol. A deep red solution forms from which the condensation product crystallizes after a short time as green crystals having a bronze luster. The mixture is stirred for 2 hours at room temperature, 150 parts by volume of water are added, the mixture is filtered with suction and the residue washed repeatedly with hot water. Yield-z 10.7 parts of an olive green powder with bronze luster. The

compound dissolves easily in dilute alkalies with a brownred color, 7

. Example 19 8.1 parts of the internal salt of 3.6-dichloro-9-phenylxanth-hydrol-2-sulfonic acid, 6.8 parts of sodium dehydrothio-para-toluidine sulfonate, and 50 parts by volume of methanol are rapidly mixed. The starting compounds dissolve very soon. From the deeply colored solution the condensation product crystallises in microscopically small violet crystals. Stirring is continued for 1 hour at 20 C.-25 C. and 11 parts by volume of a solution containing 20 parts of potassium acetate in 100 parts by volume of methanol are added. The potassium salt of the condensation product commences to crystallise. After 30 minutes it is filtered oil. with suction and washed, first with a little methanol and then with acetone. The filter cake has a marked bronze luster. Yield: 9 parts of a violet powder which is slightly soluble in cold water and easily soluble in hot water. The condensation product dyes cotton'directly in red-violet tints.

Example 20 9.7 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-Z.4'-disulfonic acid are stirred for 15 minutes with 50 parts by volume of methanol. parts of aniline are added, whereupon the solution at once assumes an intensive red coloration. The condensation product separates in a form that can easily be filtered. Stirring is continued for 2 hours and the product is filtered with suction and washed with methanol. The brown somewhat bronze filter cake is stirred with 100 parts by volume of hydrochloric acid of percent strength. The product is again filtered with suction and washed with very dilute hydrochloric acid. Yield: 5.8 parts of a brown voluminous powder which dissolves easily in dilute alkalies with a yellow-red color.

Example 2] 6 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2-sulfonic acid are stirred, at room temperature, with 6.5 parts of ammonium 4-amino-diphenylamino-Z-sulfonate in a mixture of 80 partsby volume of methanol and parts of water. Crystals of a dark color separate after a short time from the dark violet solution. On completion of the reaction they are filtered OK with suction. The condensation product can further be purified by dissolving it in sodium carbonate solution and salting out. It dyes wool and silk, according to its coloring strength, in gray and black tints which are fast to light and washing.

Example 22 12 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2-sulf0nic acid are reacted at 50 C.60 C.

with 7 parts of sodium l-aminobenzene-3-sulfonate in 80 parts by volume of glycol. The condensation product separates in the form of brick red crystals. It is filtered off with suction, dissolved in a little water with addition of a little sodium carbonate and salted out with magnesium chloride.

Example 23 Example 24 64 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2',.4-disulfonic acid are heated, for 5 hours at 50 C., with 2904 paltsof l-methylamino-Z-methyl- Example 25 If the internal salt specified in Example 24 is condensed with mesidine instead of with l-methylamino-Z- methylbenzene, a bright red powder is obtained when applying the same method of Working.

Example 26 9.4 parts of the internal salt of 3.6-dich loro-9-phenylxanthhydrol-4-meth0xy-2'-sulfonic acid in 50 cc. of methanol are heated for 1 hour to gentle boiling with 5 parts of l-amino-4-methylbenzene and worked up as described in Example 24. The condensation product consists of a red powder.

Example 27 5 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-4'-carboxy-2'-sulfonic acid in cc. of methanol are heated for 2 hours to boiling with 3 parts of 1-amino-4-ethoxybenzene. The mixture is poured into dilute hydrochloric acid, filtered with suction and the residue washed with water. The condensation product is obtained in a good yield as a red powder.

Example 28 4 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2-sulfonic acid and 50 parts by volume of methanol are stirred, for 4 hours at 20 C., with 1.5 parts of 1-ethylamino-2-methylbenzene. By addition of water the condensation product is precipitated and is then dried. It consists of a dark brown powder.

Example 29 4 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfonic acid and 50 parts by volume of methanol are stirred for several hours with 1.7 parts of butylaminobenzene, in the course of which the condensation product partly precipitates. In order to complete the precipitation water is added, and the precipitated mass is dried. A dark brown powder is obtained.

Example 30 4 parts of the internal salt of 3.6-dichloro-9-phenylxanthhydrol-2'-sulfonic acid, 50 parts by volume, of

methanol and 1.5. parts of ethylaminobenzene are con densed for 6 hours at room temperature. The product is filtered with suction and dried. The final product consists of a red-brown voluminous powder.

Example 3] 4.5 parts of the internal salt of 3.6.4-trichloro-9-phenylxantl1hydrol-2'-sulfonic acid, 50 parts by volume of methanol and 1.5 parts of l-ethylaminobenzene are stirred at room temperature. The condensation product is isolated by precipitation with water. After drying it consists of a red-brown powder.

Example 32 4.5 parts of the internal salt of 3.6.4-trichloro-9-phenylxa11thhydrol-2'-sulfonic acid, 50 parts by volurnq of water and 3 parts of sodium 4-aminodiphenyl ether-2- sulfonate are condensed at 30 C.- C. Subsequently the product is salted out by addition of sodium chloride; it is then filtered and dried. 5 parts of a black-brown condensation product are obtained.

2,794,023 9 10 We claim: 5. The compound of the formula 1. Xanthenium compounds of the general formula E on R1 01 o N 1-0 1) O-ooo11 so l "s03 6. The compound of the formula L I wherein R1 stands for a member of the group consisting Z of hydrogen and lower alkyl, R2 means a member selected 3 0 N from the group consisting of radicals of the benzene series, N-ethyl-carbazole and 1-pheny1-3-methyl-5-pyrazolones and R3 stands for a member of the group consist- Q ing of hydrogen, chlorine, the methoxy, the carboxyl, O 1

and the sulfonic acid group.

2. Xanthenium compounds of the general formula H 01- O\ N 7. The compound of the formula R: H c. 1

so H wherein R2 stands for a member selected from the group S0a 3 consisting of radicals of the benzene series, N-ethylcarbazole and 1-pheny1-B-methyl-S-pyrazolones.

3. The compound of the formula References Cited in the file of this patent H Cl 0 I 1 UNITED STATES PATENTS 2,071,130 Krzikalla, et a1. Feb. 16, 1937 \C -0CH; FOREIGN PATENTS 18,017 Great Britain July 2, 1898 466,823 Canada July 25, 1950 5 848,231 Germany Sept. 1, 1952 OTHER REFERENCES Gibbs a 31.; J. A. c. s., vol. 50, pp. 1755-1762 1928 The Orndorfi et al.: J. Am. Chem. Soc., vol 46, pp. 1896- 

1. XANTHENIUM COMPOUNDS OF THE GENERAL FORMULA 